Conventional connectors for the type of service addressed by this invention typically utilize mating parts having a plug member with a contact portion of substantially cylindrical shape for insertion into a cylindrical cavity in a socket member. Because of the working clearance required, solid plug contact configurations fail to make a positive electrical contact and are easily uncoupled by accident; therefore, the cylindrical plug contact is usually made in a bifurcated configuration, typically prestressed by spreading the two halves apart slightly in an attempt to maintain positive retention force between the plug contact and the wall of the cavity. This type of connector has proven unsatisfactory under the rigors of field usage: inherently the area of actual contact tends to be small, thus oxidation and other contamination degrade areas not in actual contact; and over time, with repeated decoupling and recoupling, stress relaxation in the metal plug contact material, which is typically brass, along with wearing away of both plug and socket material, frequently renders the connection loose, easily decoupled by accident, and prone to intermittancy and damage from arcing, thus generally unreliable and hazardous. In reaction to such problems, there has been a trend for safety regulatory agencies to disapprove connector types which fail to provide a positive, reliable method of contact and to mandate at least some form of locking means to prevent accidental decoupling under rigorous service conditions. Even when fitted with locking means, for example of the bayonet type, and whether or not bifurcated and prestressed, connectors of the known type utilizing parallel cylindrical surfaces as the major contact area inherently fail to provide positive contact presssure over the entire intended contact surface area, and this failure worsens with decoupling and recoupling, so that the reliability of such connectors generally fall far short of a satisfactory level.